1. Field of the Invention
The invention presented herein relates generally to sensors for detecting radicals, energetic radiation, plasma or heat. More specifically, the present invention relates to sensing devices for the detection of peroxide radicals and reaction initiators.
2. Description of Related Art
Microcantilever-based chemical and biological sensors can be fabricated by coating a commercially-available cantilever to enhance sensitivity and induce chemical selectivity through the choice of coating material. Depending on the choice of coating, the cantilever can be used to detect specific chemical compounds as well as proteins, DNA segments, and other biomolecules. Microcantilever chemical and biological sensors operate by responding to interactions with external stimuli in that an absorbed mass of analyte molecules causes nanomechanical bending of the microcantilever. The change in mass on the microcantilever surface due to the binding of the analyte molecules is proportional to the deflection of the microcantilever. Instead of measuring the surface stress induced due to adsorption of molecules, it is also possible to detect an added mass or an induced temperature change. Mass detection requires a resonant cantilever where the added mass is detected as a change in resonant frequency of the cantilever. Temperature changes on the surface of a cantilever can be detected by using a cantilever consisting of a sandwich of materials with different coefficients of thermal expansion. The deflection can be detected by using optical readout. The microcantilever response such as, for example, resonance frequency, phase, amplitude, Q-factor, and deflection can be simultaneously detected.
Bending and resonance response of a microcantilever are typically measured using techniques associated with atomic force microscopy (AFM). These techniques include optical reflection, piezoresistive, capacitive, and piezoelectric methods.